Project Summary/Abstract Among the 62,400 Youth Living with HIV (YLH) aged 12-24 years old, 36% are linked to health care and only 6% of YLH are virally suppressed.1 It is imperative that YLH achieve viral suppression in order to reduce the probability of infecting others, as well as increasing the length and quality of their own life. Stepped Care is a strategy used in managing other chronic diseases, not yet applied to HIV. Providers implement the least intensive intervention needed to achieve the treatment goal and intensify the intervention until the treatment goal is achieved. Study 2 tests a Stepped Care Model to achieve viral suppression ? by increasing adherence to the HIV Treatment Continuum. This U19's strategy for retaining the cohort, monitoring outcomes, and linking YLH to care is the Standard Care Condition in Study 2 (labeled Prototype Retention/Prevention Strategy in other cores or studies) and will be combined by an Automated Messaging and Monitoring Intervention (AMMI) for YLH. The Stepped Care arm will have three levels of intervention: Level 1: Standard Care; Level 2: a Peer Support and AMMI (PS-AMMI) plus the Standard Care; and Level 3: a Coach plus PS-AMMI plus the Standard Care. The PS-AMMI and Coaching will be both in-person contacts, as well as on social media, texting, and probes to monitor behaviors over time. Having a detectable viral load at a 4 month assessment, triggers increasing intensity in the level of intervention provided. YLH with established HIV infection (N=220) will be identified by screening each youth seeking services at five homeless shelters and gay-identified community based organizations in Los Angeles and New Orleans. The sample is expected to be 79% male Gay, Bisexual, and Transgender YLH (GBTY), 5% heterosexual males, 71% African-American, 15% Latino, and 16% female. The YLH will be randomly assigned during the recruitment process when it is determined that the YLH has an established HIV infection by the interviewer in the Recruitment, Engagement, and Retention Center (RERC).Over 24 months, viral load will be monitored as the primary outcomes with dried blood spots. Secondary outcomes will be sexually transmitted infection (STI), serious substance abuse, and retention in care and antiretroviral (ARV) therapy adherence. The study will examine the mediating effect of reducing substance use and reducing depression on viral suppression, as well document the frequency and type of life challenges and barriers YLH experience to achieve viral suppression and how the quality of the peer support and coaching may impact outcomes. The results of this study will potentially influence CDC's policies on how to diffuse evidence-based practices and provide CDC with good estimates on the costs of repeat testing among GBTY.